Kingman EMS and sheriff's deputies were called to the 2000 block of SE 50th in Kingman County at around 2:45 pm.
Authorities say the 53-year-old man, who is from Claflin, was doing business in the area and told police he was looking for a pen in the console of the vehicle.
He moved the .45 caliber handgun, which belongs to him, to get to the pen. But, the gun discharged and struck him in the leg.
He was taken to a Wichita hospital for treatment. As of Thursday morning, he's listed in fair condition.
The incident is under investigation.